Telephone



(N0 Model.)

lllhnumlimmm mun . W. MQDONOUGH.

4 Sheets Sheet 1.'

TELEPHONE;

Patented Oct. 21, 1890.

4 Sheets-Sheet 2.

Patented Oct. 21, 1890.-

F I w wr II In! ll -J. W. MQDONOUGH.

TELEPHONE.

(-No Model.)

(No Model.) 4 Sheets-Sheet 3..

J. w. MQDON OUGH.

TELEPHONE.

No 438,818. Pate'ntedOoL-Zl, 1890..

(No Model.) 4 Sh'eets-S heet 4.

J. w. MQQDONO'UGH.

TELEPHONE. No. 438,818. v Patented 001;. 21, 1890.

%@M/% I m am ME-QQYM 2 a i r for a condenser to UNITED STATES JAMES IV. MCDONOUGH, OF NEW YORK, N. Y.

TELEPHONE.

SPECIFICATION forming part of Letters Patent No.

438,818, dated October 21, 1890.

Application filed March 9, 1888- Serial No. 266,663. (No model.)

To to whom it may concern.-

Be it known that I, J AMES W. MODONOUGH, a citizen of the United States, residing at New York, in the county and State of New York, have invented certain new and useful Improvements in Apparatus for Electrically Transmitting Articulate Speech and other Sounds, of which the following is a specification, reference being had to the drawings accompanying and forming a part of the same.

My invention relates to a method of telephoning; and it consists in the appliances and apparatus made use of in carrying out the same.

The invention is more particularly applicable to long-distance telephony or systems in which telephonic intercommunication is established over circuits of great length; but it is capable of being used generally under practically the same conditions as other telephones.

To accomplish the objects of my invention I seek to produce on the line leading to the receiving-instrument a rapid succession of distinct and separate electrical impulses constituting what is known as an intermittent current. To produce a current of this character capable of acting on a-telephonic receiver so as to cause it to reproduce articulate speech, I use, in conjunction with certain other appliances hereinafter set forth, one or more condensers. These devices constitute in their combination the transmitter proper, and for the receiver I employ any of the ordinary telephonic receivers now in use. The transmitting mechanism is so organized that it takes up a battery-current, as varied or modified by the human voice or by any other sound through the instrumentality of a suitable device, and transfers it from the local circuit to an independent or separate line or circuit leading to the receiver, at the same time con verting it into an intermittent current. For this purpose I use in combination with one ormore condensers a circuit shifter or controller acting to connect the plates or poles of V the condenser or condensers alternately to theloc'al circuit and the main line, or, in other words, alternately to charge the condenser by the'varied local current and to discharge it into the line. Inasmuch as the time required discharge is very much less than that which, under these circumstances, at least, is required to charge it, it is evident that the current, whatever its condition or character may be in the local circuit, consists, when delivered to the main line, and thus when it reaches and acts on the receiver, of

a succession of independen t separate impulses or discharges, and that these varyin theirintensity and consequently in their effect upon the receiver with the varying strength of those portions of the local current to which said impulses respectively correspond, and so with the varying strength of the corresponding parts of theair Vibrations, which, by their action on the transmitting mechanism, give character to the local current. This being the general character of the means by'which the invention is carried into effect I will now, by reference to the drawings, explain the details of the same and indicate in what ways they may be modified.

Figure 1 shows in perspective the exterior of one form of the apparatus when arranged for use. Fig.2 isa partly diagrammatic view of a simple form of the transmit-ting apparatus. Fig. 3 is a perspective view with diagrammatic connections of a modified form of transmitter. Fig. 4: is a diagram of the details and circuit-connections of Fig. Fig. 5 is a modification of the same. Fig. 6 is a plan view of another modified form of apparatus, containing also the circuit-connections diagrammatically shown.

Referring to Fig. 2, which serves to illu's-' trate the principle of operation of the invention generally, L L represent a main line or circuit containing an ordinary telephonic receiver R. The means for modifying or varying the current to operate the receiver comprise the remaining appliances shown. Of these T is a microphone or any other telephonic instrument capable, when acted on by the human voice or by other sounds, of producing changes in the local current corresponding to the sound-waves that excite it. It is included in the local circuit twith a battery B and the primary 0 of an inductioncoil.

I mount in a suitable box or frame A a metal disk A, which may be revolved at high speed by a train of gears A driven by springs, weights,

or otherwise. The periphery of this in the instrument T during such time.

wheel or disk is serrated, and insulatingblocks are fitted in between the teeth, form ing a smooth and even peripheral surface. Two contact-springs b c bear upon the periphery of the wheel, and a third contactspringa bears upon the side of the disk or upon the circular shoulder thereon, in the manner illustrated. The contacts I) and c are so disposed that both are never in contact with the metal at the same time. The spring a, on the other hand, being always in contact with the disk,is brought alternately into electrical connection with the springs 19 and 0. One end of the wire or circuit S, including the secondary C of the induction-coil, is connected to one of the contact-springs, as b, and the other end of the conductor S is connected to one of the terminals of a condenser D. In like manner the ends of the circuit L are connected, respectively, to the same condenser terminal and to the other contact-spring c. A wire S connects the opposite terminal of condenser D with the contact-spring a. The operation of this system is as follows: The disk A is set in rapid uniform rotation. Then by speaking into the instrument T the local current in the primary wire t of the induction-coil is varied or modified, and the changes thus produced in the intensity of this current excite currents in the local secondary circuit S S. These secondary currents, however, do not pass to the receiver R, but flow into the condenser whenever the spring I) is in contact with the metal teeth of the disk A. When the springc comes in contact with one of the metal teeth, the condenser is discharged intothe main line. The time occupiedin charging thecondenser is that required for one of the metal teeth of the disk A to pass under the spring I), and the strength of any particular charge will depend upon the character of the movement taking place The time required to discharge the condenser, on the other hand, is very much less than that occupied in charging it, the discharge being practically instantaneous whatever the strength of the charge, while the charging is gradual and consumes an appreciable period of time. It follows that the current in line L is made up of a succession of sharp, quick, and absolutely-distinct impulses formed by the condenser-discharges. At thesame time it is found to reproduce in the receiver R the words or sounds directed into the instrument T. Such an apparatus may be put up in a commercial form in the manner shown in Fig. 1, in which the various devices are inclosed in boxes or cases secured to a board A i In the drawings, T is the instrument for varying or modifying the current to be sent into the condenser. E is the battery-box. A contains the circuit-shifter, and D the condenser.

It is' desirable for the attainment of the best results that as much of the current in the local as is practicable should be transferred to the line in the above-described mantion of the shaft.

: charged at the same time.

the brushes 0 p q 'r's' t are also adjusted so that I therefore find it advantageous to employ a number of disks like the disk A, above described, and to multiply the other appliances accordingly. In Fig. 3 I have shown an apparatus of this kind containing six of such disks. This device consists of six independent metal disks or wheels (designated by the local circuit S is electrically connected to the three springs 0 p q, and the other wire is similarly connected to the springs r s t. In like manner one terminal of the main line is electrically connected to springs to v w, and

the other to springs w 1/ z. The terminals of the three condensers D D D", are respectively connected to springs 2' Z j m and 11..

'Each wheel has twenty-four metallic teeth and a corresponding number of insulatingspaces, each of which is slightly more than twice as longas a metallic tooth. The wheels are insulated from one another, and so set that the teeth and insulating-spaces on wheels 1 2 3 correspond exactlyin position with those on the three remaining wheels, so that, for instance, while brush a is in contact with a metallic tooth on Wheel 1 brush as will be in contact with a metallic tooth on wheel 4, and so on for all the others. The relative length l of the insulating and conducting portions of the peripheries of the wheels brings all the brushes u v w avg z upon insulation for a moment at the instant when any two of the brushes, as u .2, have passed over the metal teeth, or seventy-four times for each revolu- The same is true of the brushes 0 p q rs t. From this. it follows that only one condenser can be charged or dis- The positions of both of the brushes bearing on the periphery of any one of the wheels may never be in contact with metal teeth at the same time. As a result of this the local circuit S isnever in direct connection with the line L. This dis 3 position of the parts, together with the action of the instrument, will be more clearly understood by reference to Fi 4, in which the apparatus is shown diagrammatically, corresponding parts being similarly designated.

Assuming that thewheels are'being rapidly rotated from a suitable source of power, their action in transferring the current of circuit 1 S to the lineL will be as follows: At agiven point of time during the revolution of the wheels the brushes will be in the positions shown in Fig. 4=that is to say, the brushes 0 r bear on the metallic teeth of wheels 1 and 4. The metal portions of these wheels being in constant electrical connection through ICC IIO

brushes i Z with the terminal of condenser D,

the latter will receive a charge, there being no other path for the current through the said wheels,'inasmuch as the line-brushes use. 4 are at the time on insulation.

- metal teeth and the local brushes q t on insulation. The condenser D, being thus connected with the line, discharges in to the same. In this manner as the wheels rotate withthe shaft the condensers are alternately charged from circuit S and discharged into line L, one

condenser, as D, being charged while a second is discharging and the third being out. So by the further rotation of the wheels condenser D will next be charged, condenser D discharged, and condenserD cutout, and so on. The independent impulses, pulsations, or discharges thus thrown onto the line reproduce in an ordinary telephonic receiver the words or sounds directed into the instrument T.

Inillustration of another way in which the principle may be carried out I now refer to Fig. 5. In this case three wheels 7 8 9, similar to the three above described,.are mounted on the shaft and insulated from one another. Three brushes or contact-springs bear upon each wheel-two ontheperipheryand the other on the circular shoulder or flange. Of the two brushes which bear on the periphery one will be on metal, the other being on insulation, or both may be on insulation,but never both 011 metal at the same time. The brushes r st are electrically connected to one branch of the main line L. The brushes 0 p q are connected to one branch of the local circuit S, and the.branches 2' j k, respectively, to one of the terminals of the three condensers D D D The opposite terminals of these condensers are connected by wires I'm at to the conductor S L, which is connected to the two circuits S and L. The action of this apparatus is as follows: The current in circuit 75, properly varied or modified by the instrument T, induces currents in the secondary coil 0. wheels are in the positions shown the brushes q and It, being on metal, complete the circuit of the secondary coil 0 through the condenser D", which at this moment, therefore, receives a charge. Both of the brushes .910 being on insulation the condenser D is out of action entirely, while at the same time the circuit of the main line is complete through the condenser D, since brush 0" is in contact with the metal portion of the wheel 7. Alike result follows from the further rotation of the wheels, one condenser being charged while another is discharging, and the third being out of circuit. It will result, asin the former cases, that the receiver will be acted upon by At the moment when the disks or' a series of separate and independent electrical imp ulses. 1

In Fig. 6 is shown an instrument for accomplishing the same results andin which the requisite conversion of the current is efiected by means of a vibrator acting in combination with a condenser. P is an insulating base-board provided with five binding-posts. Upon this base is mounted an electro-magnet M, in front of whose poles is a vibrating magnetic strip or reed N, one end of which is set in a conductingpost M. tain the reed in vibrationethat is to say, an adjustable contact-stop N is placed in front Ordinary devices are used to main of the magnet M and the circuit-connections:

made from a battery B to the binding-posts 13 and 14:, which are connected by the conductor b b, the coils of magnet M, the post M, reed N, and stop N. This circuit being made and broken between the reed and stop:

N the reed, by the interrupted attraction of the magnet, is maintained in rapid vibration. The free end of the reed has platinum contact-points on opposite sides, and vibrates between the ends of the two levers E and F.1

platinum contacts, but leaving a slight spacer on each side, so that when the reed is vibrated by the magnet the said contacts may touch the levers alternately. As in previous figures, the circuit t contains the battery B, the instrument T, and the primary Got an induc tion-coil. One wire fromthe secondary leads through binding-post 10,which connects with lever E, and the other is connected to one terminal of a condenser D. The main line or circuit is partially formed by the conductors L L, one of which leads from the receiver R to the same terminal of the condenser, to which is connected wire S, and the other to binding-post 12, which is connected to lever F. A path common to both circuits is formed by the conductor S L from the opposite terminal of the condenser D to bindingpost 11, which is in permanent electrical connection with the post M and reed N. It results from this arrangement that by the vibration of the reed N, as above described, the local circuit S and line-circuit L are alternately completed through the condenser D, but are never connected directly together. Any impulses or currents on the main line, therefore, must come from thelocal entirely through the charging and discharging of the condenser D, and, secondly, since the time occupied by the condenserin discharging is very much less than that required to charge it, it follows that whatever be the character of the currents in the local the current in the mainline, which causes the receiver R to reproduce the words spoken intothe instrument T, is made up of a rapid succession of separate and distinct impulses or pulsations. If, in the case of this instrument, the bars or levers E F are ad justed so far apart that the vibrating reed does not touch them, the reed gives oil a musical tone; but if the reed forcibly strikes the levers the tone is broken and an effect produced in the receiver R which resembles the well-known frying. sound often heard in telephone-receivers. It is notloud enough, however, seriously tointerfere with the sounds transmitted through the line.

The operation of the instrument isreadiIy understood from the foregoing. By contact of the lever E and reed N the condenser D receives a charge. Then by the shifting of the reed and the contact of lever F therewith this charge is thrown on the main line. Such charges and discharges following in rapid succession reproduce in the receiver the words and sounds directed into the instrument '1.

Having now explained the nature oi'myinvention and the means by which it may be carried into eflect, I would state that I donot claim, broadly, the: combination, with a telephonic circuit, of one or' more condensers, as

condensers have heretofore been used in variousways in telephony. For example,.I do not claim as" my invention the combination of a condenser with an induction-coil to prevent sparkinggnor those systems in which the over- K flow of a condenser is sent along with the 1 battery-current, nor those in which the con- 1 denser is simply connected up in line to di- I vide it, nor those in which a condenser is used either as a transmitter or a receiver.

The method of telephoning or transmitting articulate speech and other sounds involved herein I have madethe subjectofanother application, Serial No. 283,785,. filed August 25, 1888, and do not claim it herein.

What I claim is- 1. In a telephone system, the combination, with a local circuit in which circulates a current varied or modified to correspond to the elements or waves of the vocal or other sounds to be transmitted, of a main or line circuit, a

' condenser or series of condensers, and one or i more circuit-shifters for alternately connecting the condenser or. the series of condensers successively to the two circuits, as set forth.

2. In a telephone system, the combination, with an induction-coil, a battery, and an insm'ument for Varying or modifying the current to correspond to the elements or waves of the vocal or other soundstobe transmitted, included in the primary circuit thereof, of a main or line circuit,- one or more condensers, a circuit shifter or shifters adapted to alternately connect the: condenser 0r condensers successively to the secondary and main circnits, as and for the purposes setforth.

JAMES W. MCDO'NOUGH. YVitnesses:

SAMLM A. DUNCAN, ERNEsr HOPKINSON. 

